Rapping mechanism for precipitator



Sept. 6, 1955 J. F. VALVO RAPPI NG MECHANISM FOR PRECIPITATOR Filed Nov. 6, 1953 llIIIIIIIIIIIIIIIIIIIII'III INVENTOR. Josep/z F l a/Vo BY ATTORNEY United States. Patent M RAPPING MECHANISM FOR PRECIPITATOR Joseph Francis Valvo, Wellsville, N. Y., assignor, by mesue assignments, to Apra Precipitator Corporation, New York, N. Y., a corporation of Delaware Application November 6, 1953, Serial No. 390,654

3 Claims. (Cl. 183-7) This invention relates to electrostatic precipitators of the rotary type; it is directed particularly to a cleaning mechanism for such a precipitator which will mechanically remove dust particles from the surfaces of the precipitator elements on which they have collected.

Cleaning devices that operate satisfactorily are frequently complicated and usually necessitate shutting off the entire electrical power supply before they can be efficiently operated. Furthermore, it is considered difficult to apply a mechanical cleaning force over more than a very limited area at any one time with the obvious result that the overall efficiency of such devices is seldom high.

This invention is especially directed to a rapping mechanism which imparts a series of sharp vibrations to a mass of collecting elements to dislodge the deposited dust particles therefrom. In device of this type, it is customary to direct the force of such rappers at only one or two points on the frame of the collecting elements where the strength of the unit is sufficient to sustain sharp vibrations from the rapping mechanism. Since these vibrations are seldom severe enough nor continuous enough to produce a vibratory movement over the entire collecting element suflicient to remove most of the particles deposited thereon, it becomes a principal object of this invention to provide a mechanism which imparts a series of vibrations of such strength to the collecting surface of a precipitator having a rotary cleaning hood that most of the deposited dust particles will be readily removed.

More particularly, this invention pertains to apparatus for automatically raising a series of striking members to a position above a plurality of stationary blocks or anvils mounted on the collecting elements of a precipitator and then releasing said striking members to fall freely upon the stationary blocks so as to provide a sharp vibratory movement throughout said collecting elements suflit cient to loosen the dust particles from the surface on which they have been collected.

Another object of this invention is to provide an improved rapping mechanism which is continuous in its operation and which in no way interferes with normal operation of the dust collector.

An exemplary manner of realizing the above mentioned and still further objects of this invention may be more clearly understood by reference to the accompanying drawings in which:

Figure l is a plan view of one sector of a rotary electrostatic precipitator.

Figure 2 is a sectional elevation showing a rapping mechanism with reference to the cooperating precipitator elements.

The apparatus illustrated in Figures 1 and 2 comprises a single wedge shaped sector of a rotary precipitator having a cylindrical stator shell carrying a plurality of radially spaced precipitator sections 24 each of which is further subdivided into a large number of individual axially positioned tubular collecting elements.

Axially positioned within the stator shell 20 is a cylindrical shell 26 joined to the inner surface of said stator shell by a plurality of radially extending support bars 30. A pair of these bars provides a frame supporting therebetween the precipitator stations 24 housing the mass of collecting elements. Each precipitator section is' trapezoidal in section when viewed in the manner disclosed in Figure 1 whereby a series of abutting sections substantially fill the wedge shaped space between a pair of radially extending bars 30 so as to comprise in effect, a wedge shaped mass of collecting elements.

Each precipitator section has fixed outwardly to its drical shell 26 and is connected by conventional trans mission means to a power source for rotating the shaft about its longitudinal axis. Normal to the upper end of shaft 52 is a wedge or sector shaped hood member 56 which is fixed thereto so as to rotate integrally with said shaft. Seals 62 are joined to the circumferential edge of the stator shell 20 to bridge the space between the rotor shell and the inner face of the hood members so as to preclude the passage of air or gas therebetween. The hood extends radially past the stator shell to provide a space outwardly on the lower face thereof on which a series of striking cams 68 are fixed to cooperatively engage the crank arm 82 of a shaft 70.

Centrally positioned within the space 64 is cam shaft 70 rotatably connected to the shell 26 by bearing 74 and extending radially outward through a bearing 76 positioned in the stator shell. After passing through bearing 76 the cam arm is bent normal to its radial axis to form an oscillating crank arm 82 which terminates at a point adjacent the striking cams 68. That portion of the shaft 70 lying between cylindrical shell 26 and stator shell 20 is provided with a series of crank arms 78 positioned removed from the oscillating crank arm 82. A striking weight 84 loosely hung from each crank arm 78 by means such as cable 86 is pre-arranged to contact the stationary block or anvil 88 below it when the crank arms 88 are inclined downwardly, and to be lifted therefrom when the crank arms are moved about their longitudinal axis. Blocks 88 are positioned to provide a minimum of one block for each precipitator section. However, by placing each block so as to extend radially over the edge of one section onto that of another it is possible for each. block to contact the edges of two sections in the manner shown in Figure 2.

In operation, shaft 52 is slowly rotated about its axis by any suitable motive power and transmission means not here shown. As shaft 52 rotates it carries therewith sector shaped hood 56 which sequentially covers each wedge shaped compartment containing a number of precipitator sections 24 and its simultaneously slides the cams 68 over the oscillating crank arm 82. Striking weights 84 hanging loosely from crank arms 78 provide a constant biasing force to maintain the distal end of oscillating crank arm 82 in substantial contact with successive strikingcams. As the hood rotates, the oscillating crank arm 82 rides the cams 68 whereby an oscillating movement is imparted to the arm 82 and to the crank arms 78 lying in the annular space 64. As the crank arms oscillate, striking weights 84 are repeatedly raised and dropped upon the stationary blocks 86 to impart to each of them a sharp rap which, when transmitted to the spring mounted precipitator sections, tends to dislodge the agglomerated dust particles and induce them to fall Patented Sept. 6, 1955 to the. bottom-of the precipitator where they may be removed.

From the foregoing description, it is apparent that the present invention provides a cleaning mechanism for a rotary electrostatic precipitator which operates continuouslyto remove collected dust particles from the surfaces thereof. Since the cleaning operation is continuous, there is in no event a great'build up of collected dust particles and the cleaning efiiciency of the precipitator is constantly maintained at a high level.

While I have described my invention with reference to a particular embodiment thereof, it will be understood that changes may be made therefrom without departing from the spirit and scope of the invention as described in the specification and set forth in the appended claims.

What I claim is:

. 1. An electrostatic precipitator for the removal of dust particles from a gas stream comprising; a pair of concentric cylindrical shells forming an annular space therebetween; radial support beams extending between cylindrical shells dividing the annular space into a plurality of Wedge shaped compartments; an assembly of grounded collecting elements suspended from each pair of adjoining support beams; a radially disposed crank arm rotatably supportedfrom the concentric cylindrical shells in each space above the collecting elements; weights depending from each crank arm and arranged to rest upon said collecting element sections when the crank arm is said rotor post and extending radially past the peripheral edge of said stator shell; and means fixed to said hood member outwardly of the stator shell to cooperate with the crank arm and effect an oscillatory motion thereof whereby said Weights are repeatedly raised from and dropped upon the sections of collecting elements when said hood is rotated about its axis.

2. An electrostatic precipitator according to claim 1 wherein the means subjecting the crank arm to oscillatory movement comprises a cam arrangement on the underside of said hood member.

3. An electrostatic precipitator according to claim 1 wherein the collecting tube assembly is separated from the radial support beams by resilient mounting means.

References Cited in the file of this patent UNITED STATES PATENTS 1,454,255 Weiskoff May 8, 1923 FOREIGN PATENTS 899,783 France June 11, 1945 

